Temperature optimization for broad-band quasi-phase-matched difference frequency generation

The temperature-tuning prosperities of quasi-phase-matched (QPM) difference frequency generation (DFG) in a uniform periodically poled LiNbO₃ (PPLN) device are studied theoretically in the near degeneracy limit. Combining the theoretical and numerical analysis results, the paper shows that through the tuning of temperature, the conversion efficiency and bandwidth can be changed considerably. This paper proposes a PPLN device consisting of several segments of different temperature to obtain a more desirable performance for the QPM-DFG. The optimizations for temperature are studied in detail by the use of a cascading technique, and they show that broadening of the conversion bandwidth will reduce the conversion efficiency. A better performance of uniform PPLN can be obtained owing to the reconfigurable and adjustable abilities of multisection temperature tuning.